Oil containing asphaltenes and paraffins is produced by certain oil wells. Such high molecular weight cyclic materials are, in extreme cases, in colloidal suspension in the crude oil.
In particular, colloidal asphaltenes tend to act as stabilizing agents for emulsion of water in the crude oil. Such emulsion is considerably more viscous than the crude and, consequently, increases the difficulty of removing the crude from the ground.
Asphaltenes and paraffins tend to precipitate from the crude as the temperature is lowered, as occurs when the oil leaves the formation and goes into the well bore. Co-precipitates form with any paraffins that may be in the oil and with inorganic materials, such as calcium carbonate, migrating clay particles, calcium sulfate, and the like. In an extreme case, such deposits may essentially stop the flow of oil from the well. Acidizing is used to remove the inorganic constituents, including conversion of insoluble sulfate salts to the more soluble carbonates.
In U.S. Pat. No. 3,819,520, Jones, et al., teach that a mixture of an octanol and a lower alcohol, such as ethanol, isopropyl alcohol, normal-propanol, or tertiary-butanol, can be used to acidize oil and gas wells. However, they exclude methanol from their composition and point out that methanol has too little solubilizing action for octanols. Contrary to this, it has now been found that a mixture of methanol and ethanol, isopropyl alcohol, normal-propanol, or tertiary-butanol, or any combination thereof dissolves C.sub.8 -alcohols and solubilizes asphaltenic deposits better than a miscible solvent containing only a propyl alcohol and C.sub.8 -alcohols.